Development of a rat forelimb vascularized composite allograft (VCA) perfusion protocol

Area of Science:

• Transplantation research
• Surgical innovation
• Organ preservation

Background:

• Vascularized composite allografts (VCAs) are crucial for restoring form and function after limb loss.
• Rat limb VCA models are vital for studying transplant pathophysiology.
• Current models predominantly use hindlimbs, which differ anatomically from clinical upper extremity transplants.

Purpose of the Study:

• To optimize procurement and sub-normothermic machine perfusion (SNMP) protocols for rat forelimb VCAs.
• To compare forelimb VCA perfusion parameters with established hindlimb VCA protocols.
• To assess the impact of perfusion parameters on cellular viability in rat forelimb VCAs.

Main Methods:

• Development and refinement of rat forelimb VCA procurement techniques.
• Implementation of sub-normothermic machine perfusion (SNMP) for rat forelimb VCAs.
• Comparative analysis of perfusion parameters (flow rate, pressure) and outcomes (cellular damage markers) between forelimb and hindlimb VCAs.

Main Results:

• Rat forelimb VCAs require distinct perfusion parameters, specifically lower flow rates and higher acceptable maximum pressures compared to hindlimbs.
• Low-flow perfusion in forelimb VCAs resulted in reduced cellular damage, evidenced by oxygen uptake, edema, potassium levels, and histology.
• These findings were observed within a 2-hour machine perfusion timeframe.

Conclusions:

• Optimized SNMP protocols are essential for successful rat forelimb VCA preservation.
• Forelimb VCA perfusion parameters differ significantly from hindlimb models, necessitating tailored approaches.
• This research provides critical data to guide future studies on upper extremity VCA preservation and transplantation.